1. Field of the Invention
This invention relates to roof battens used for applying tiles to a roof, and, more particularly, to a batten product integrally-formed of plastic.
2. Description of Related Art
Tile roofs typically include several layers of materials. Over the trusses and/or rafters there is often a layer of exterior plywood or other sheathing, covered with roofing paper or felt which is conventionally applied, the tile underlayment. Roof battens are applied directly to this underlayment, with the tiles overlaying the battens.
Roof battens are conventionally produced as 1 inch by 2 inch wooden elements. Battens are typically secured to a sloping roof in generally horizontal lines, such as through nailing, screwing or stapling, at intervals dictated by the tiles to be applied over the battens. An element on the tiles is supported along the elevated back edge of the batten.
While battens are useful in applying tiles to a roof, there are deficiencies in the traditional batten, foremost among them being the tendency of such battens to collect water on the roof surface underneath the tiles. When wood battens are used, water which has seeped through or between the tiles will accumulate behind the battens and form small pools. When water collects or stands in this manner, it will often infiltrate the paper or felt layer and into the underlying structure of the roof, leading to roof deterioration, interior mold, and permanent damage.
As traditionally assembled, battens create a dam behind the tiles, which can lead to storage of water on the underlayment. This pooling can set up damage to a large portion of the felt underlayment. Even double felting a tile roof will not protect it if large quantities of water are collecting on the roof surface, as it will eventually find its way into the underlayment.
The felt underlayment should be the last line of defense, as once the underlayment has failed, moisture makes its way into the house. Once water finds its way beneath the felt underlayment, the sheathing itself begins to fail, as water will make its way to any seam and then into the house. Internal dry rot and rotting sheetrock, mold, etc., is the result.
In U.S. Pat. No. 5,570,555, issued Nov. 5, 1996, to Ferguson et al., a solution to the problem of water pooling is proposed utilizing a double batted system, with a layer of vertically disposed battens underlaying and supporting the horizontal battens that support the tile. This provides a complicated construction, with double layers of sheathing and battens required to assemble the roof.
In U.S. Pat. No. 6,393,796 B1, issued May 28, 2002, to Goettl et al., battens are proposed of formed sheet metal with an inverted vee in cross-section, with the peaked portion of the vee elevated and supporting the tiles. Small holes are provided where each leg of the vee contacts the roof surface, to supply drainage in a vertical direction along the roof surface. An additional proposed advantage for such battens is their stackability. The use of metal sheathing, however, adds to the weight and expense of this product over the traditional wooden batten.
A plastic batten with external grooves formed along one surface is described in U.S. Pat. No. 5,471,807, issued Dec. 5, 1995, to Vasquez. The grooves are disposed along the surface of the roof, to allow vertical drainage of accumulated water. However, with this design, the grooves can easily become clogged by accumulations of dirt and debris, minimizing the drainage achieved in practical application.
Another plastic batten is disclosed and claimed in U.S. Pat. No. 6,359,193, issued Mar. 19, 2002, to Morris. This patent discloses a multi-ply plastic batten with one of the plies folded to form corrugations. In the construction layers of material, the plies, are fused with one ply forming a corrugated level, and then the corrugated units are stacked and further fused, and finally cut into a batten. The resulting product has a multiplicity of passages formed by the corrugated layer in each layer of the structure for drainage in a vertical direction down the roof.
Batten designs that elevate the attachment layer over an open structure underneath, such as the double batted system, are complicated to produce and increase the cost of the roofing, in many cases requiring the use of special tiles for use with the roofing system.
Single layer battens with grooves, chambers or other openings provided for drainage and ventilation are susceptible to clogging from the dirt and debris that collects between battens on the roof surface. The debris may be left over from the construction, or originate from the activity of animals and insects, wind or rainwater. Providing more frequent holes in the current designs would weaken the batten, by increasing the non-supporting regions of the batten.
Thus there is need for a roof batten that will provide adequate ventilation and drainage to eliminate the pooling of water on the roof surface, and which is easy to produce, low in price, lightweight, strong, and easily installed.